Telecommunication equipment has benefited from the design of electrical plugs and jacks that provide easy connect/disconnect capability between electrical circuits within the telecommunications equipment and, for example, local network wiring. Such plugs and jacks are particularly popular in association with telephone sets, where they were first used, and, more recently, in association with a large variety of peripheral equipment that is connected to telephone lines. The modular plugs and jacks in use today have been standardized, insofar as their performance specifications are concerned and also insofar as certain critical dimensions and structural features are concerned. The use of these devices has become so widespread that new houses and other buildings are prewired with jacks located throughout the various rooms as well as other strategic locations, to accommodate the communication equipment. Where large numbers of such connections are needed, it is typical practice to route the wires to a central location, such as a communication closet where, typically, the jacks are mounted on patch panels. Such an arrangement is shown, for example, in U.S. Pat. No. 5,096,439 of J. R. Arnett. In most installations, it is desirable that the jack be compact, and there have been numerous jacks designed to achieve this goal. In U.S. Pat. No. 5,096,442 of J. R. Arnett there is shown one such compact jack and plug arrangement. The compact electrical connector shown in that patent includes a metallic lead frame mounted to a spring block. The lead frames comprise a number of flat elongated conductors, each terminating in a spring contact at one end and an insulation displacement connector at the other end. The insulation displacement connectors are folded around opposite side walls of the spring block and achieve compactness, and the spring contacts are folded around the front surface of the spring block for insertion into a jack frame. The front surface of the spring block includes a tongue-like projection which fits into one end of the jack frame and interlocks therewith. With the ever increasing numbers of peripheral equipment, and with concomitant increases in operating frequencies, such as required in digital data transmission, connector assemblies such as shown in the aforementioned Arnett '442 patent, while enjoying a large amount of commercial success, do not function well in the higher frequency ranges. The use of such plugs and jacks is impaired by crosstalk within the components, especially in the plug, and as frequencies increase, so does the effect of crosstalk. Numerous arrangements have been proposed for reducing the effects of crosstalk overall by connectors having a minimum of crosstalk, or by connectors which add compensating crosstalk to the overall circuit, such as adding capacitance to the jack to nullify or compensate for the crosstalk in the plug. In U. S. Pat. No. 5,186,647 of W. J. Denkmann et al., there is shown an electrical connector for conducting high frequency signals in which the input and output terminals are interconnected by a pair of metallic lead frames mounted on a dielectric spring block. The lead frames, which are substantially identical to each other each comprises several flat elongated conductors, terminating in spring contacts at one end and insulation displacement connectors at the other end. The conductors are generally parallel and close to each other, but three conductors of one frame are arranged to overlap three conductors of the other frame in a crossover region. As a result, the crosstalk between the several conductors is reduced, due to the reversal in polarities caused by the crossovers.
Nevertheless, for a wide range of applications, an electrical connector having even less crosstalk would be desirable. In particular, the rate of data flow, which is continually being increased in the art today, causes the wiring parts to become, in effect, antennae which both broadcast and receive electromagnetic radiation, thereby, in effect, coupling different pairs of wires together, (crosstalk), thereby degrading the signal-to-noise ratio, and producing an increased error rate. Connectors which, in effect, nullify or at least reduce overall crosstalk, and yet which are usable over wide frequency ranges, are desiderata to which the present invention is addressed. In order for wide frequency usage to be possible, it is desirable that at least some of the components of the connector be compatible with components of connectors in both the low and the high performance categories.
The aforementioned related applications of Jaime R. Arnett, the present inventor, the disclosures of which are incorporated herein by reference, deal with selectable compatibility connectors, plugs, and jacks wherein a connector assembly of a plug and a jack, which are designed to operate together as a high performance connector, but which automatically introduce capacitance into the connection circuit when used as a component or components of a low performance connector to alter the crosstalk performance and transmission loss characteristic thereof. The terms "high" and "low" are terms of art and relate to several connector parameters, chief among which is crosstalk, as will be discussed more fully hereinafter. It is desirable, for optimum performance, that the plug and the jack operate together in the desired frequency range. Thus a low performance jack should operate with a low performance plug, and a high performance jack should operate with a high performance plug.
In greater detail, the plug shown in those applications has mounted therein a printed wiring board which is movable in longitudinal translation in a pair of guiding slots. On one surface of the wiring board, or PWB, are a plurality of spaced capacitance contact pads, the number being dependent upon the number of leads to which it is desired to add capacitance. The wire leads in the plug which, as in normal practice, wrap around the nose of the plug, have contact portions which bear against the surface of the PWB, and against the capacitance pads of the PWB in a second position thereof, or simply against the non-conducting surface of the board in a first position thereof. The plug further includes a spring member which bears against the end of the PWB remote from the plug nose, and functions to bias the PWB toward the first, non-capacitance engaging position. Actuator means, such as stand-offs from the PWB, function to engage a portion of the jack where the jack is a low performance component when the plug is inserted therein, thus moving the PWB to the capacitance engaging position to introduce capacitance into the circuit for crosstalk compensation and to alter the transmission loss characteristic in the low performance mode. Thus the high performance plug of the invention can be used with a low performance jack.
The second component of the high performance connector of these applications is a jack which has mounted therein a PWB which is movable in longitudinal translation in a pair of guiding slots. As is the case with the plug of the invention, the PWB has on one surface thereof a plurality of closely spaced capacitance contact pads, the number being dependent upon the number of leads to which it is desired to add capacitance. The wire leads in the jack have contact portions which bear against the surface of the PWB and, in a second position, against the capacitance pads thereon, or against a non-conducting portion of the PWB in a first position. The PWB, which as pointed out before, is movable relative to the jack, and more particularly, to the wire leads therein, is biased by a spring member within the jack housing to the first or non-capacitance introducing position which is the desired position for the high performance jack. The PWB has spaced actuator stand-offs mounted thereon which, as will be explained hereinafter, are pushed by the nose portion of a low performance plug to move the PWB to the second position, thereby introducing capacitance into the connector circuit. The jack is provided with first and second spaced slots which receive the stand-offs of the high performance plug of the invention, thereby preventing them from actuating the PWB in the plug. By the same token, the plug has recesses in the sides of the housing thereof which provide clearance for the stand-offs on the PWB of the jack, thereby preventing the high performance plug of the invention from actuating the PWB of the jack.
The plug and jack of the foregoing applications are characterized by each having a printed wiring board that is movable in translation, as discussed. It is also possible, if not, in the interests of cost, desirable, to have similar selectable compatibility electrical connector assemblies in which the components, i.e., the plug and jack, having stationary printed wiring boards, and it is to such arrangements that the present invention is directed.